The present invention disclosed herein relates to an electronic device, and more particularly, to an optical Orthogonal Frequency Division Multiplexing (OFDM) receiver and an optical signal receiving method thereof, which can solve the nonlinearity of an optical modulator.
OFDM uses sub-carriers that are orthogonal to each other, for transmitting a wideband signal. In OFDM, data is modulated and transmitted at a relatively low symbol speed by each of the sub-carriers. OFDM-based communication technology is one that may cope with high spectrum efficiency and multi-fading.
Currently, an OFDM system is used as a digital modulation scheme in WiMAX, Wireless LAN, Asymmetric Digital Subscriber Line (ADSL) and digital broadcasting. Depending on the purpose of use, the number of sub-carriers and a frequency band may be different, but the fundamental modulation scheme of the OFDM system is identical. That is, in the OFDM system, modulation and demodulation are performed through an Inverse Discrete Fourier Transform (IDFT)/Discrete Fourier Transform (DFT) block. A cyclic prefix is added to the transmission signal of the OFDM system. Channel distortion or multipath fading may be compensated by the cyclic prefix. Inter-symbol interference (ISI) or inter-channel interference (ICI) may maximally be reduced through the cyclic prefix.
Because of the above-described superior communication characteristic, the OFDM system is recently applied to optical communication. Technology for applying OFDM to optical communication is called optical OFDM. Optical OFDM is recognized as technology for solving the deterioration of quality in optical communication, for example, the chromatic dispersion and polarization mode dispersion of an optical fiber. Much research for this is being made.
In optical OFDM, an optical modulator is used for converting a baseband OFDM signal into an optical signal band. However, the transfer characteristic of the optical modulator fundamentally is nonlinear. Various attempts have been made for solving the nonlinearity of the optical modulator. For efficiently solving the nonlinearity of the optical modulator, however, technology with economic considerations is still required.